papermc/Spigot-Server-Patches/0253-Ignore-Dead-Entities-in-entityList-iteration.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sat, 28 Jul 2018 12:18:27 -0400
Subject: [PATCH] Ignore Dead Entities in entityList iteration

A spigot change delays removal of entities from the entity list.
This causes a change in behavior from Vanilla where getEntities type
methods will return dead entities that they shouldn't otherwise be doing.

This will ensure that dead entities are skipped from iteration since
they shouldn't of been in the list in the first place.

diff --git a/src/main/java/com/destroystokyo/paper/PaperCommand.java b/src/main/java/com/destroystokyo/paper/PaperCommand.java
index 9cb2f3b31921870ddba044840e99eb04babe26bb..f0a836db74ad3e20778d3863223bc9a35ff4ad41 100644
--- a/src/main/java/com/destroystokyo/paper/PaperCommand.java
+++ b/src/main/java/com/destroystokyo/paper/PaperCommand.java
@@ -179,6 +179,7 @@ public class PaperCommand extends Command {
                 Collection<Entity> entities = world.entitiesById.values();
                 entities.forEach(e -> {
                     MinecraftKey key = e.getMinecraftKey();
+                    if (e.shouldBeRemoved) return; // Paper
 
                     MutablePair<Integer, Map<ChunkCoordIntPair, Integer>> info = list.computeIfAbsent(key, k -> MutablePair.of(0, Maps.newHashMap()));
                     ChunkCoordIntPair chunk = new ChunkCoordIntPair(e.chunkX, e.chunkZ);
diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
index e829f62397d092fa919d387b157a65b0c627e2e2..3cb1ee261724e34a23c4a0f98673da1597786a01 100644
--- a/src/main/java/net/minecraft/server/Chunk.java
+++ b/src/main/java/net/minecraft/server/Chunk.java
@@ -825,6 +825,7 @@ public class Chunk implements IChunkAccess {
 
             for (int i1 = 0; i1 < l; ++i1) {
                 Entity entity1 = (Entity) list1.get(i1);
+                if (entity1.shouldBeRemoved) continue; // Paper
 
                 if (entity1.getBoundingBox().c(axisalignedbb) && entity1 != entity) {
                     if (predicate == null || predicate.test(entity1)) {
@@ -862,6 +863,7 @@ public class Chunk implements IChunkAccess {
 
             while (iterator.hasNext()) {
                 T entity = (T) iterator.next(); // CraftBukkit - decompile error
+                if (entity.shouldBeRemoved) continue; // Paper
 
                 if ((entitytypes == null || entity.getEntityType() == entitytypes) && entity.getBoundingBox().c(axisalignedbb) && predicate.test(entity)) {
                     list.add(entity);
@@ -884,6 +886,7 @@ public class Chunk implements IChunkAccess {
 
             while (iterator.hasNext()) {
                 T t0 = (T) iterator.next(); // CraftBukkit - decompile error
+                if (t0.shouldBeRemoved) continue; // Paper
 
                 if (oclass.isInstance(t0) && t0.getBoundingBox().c(axisalignedbb) && (predicate == null || predicate.test(t0))) { // Spigot - instance check
                     list.add(t0);
diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index da195d9bb6995fcbe569ca2e2b08c473431376a6..49c7b40744adcd36e5ae1eef026679e9b646feac 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -190,6 +190,7 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, Ke
     protected int numCollisions = 0; // Paper
     public void inactiveTick() { }
     // Spigot end
+    public boolean shouldBeRemoved; // Paper
 
     public float getBukkitYaw() {
         return this.yaw;
diff --git a/src/main/java/net/minecraft/server/WorldServer.java b/src/main/java/net/minecraft/server/WorldServer.java
index d6c319c1177e43eebeb7d9f366da3495b38b6b97..1cbb1c3ddf45cd6d650ca274af4545f2d1c8a813 100644
--- a/src/main/java/net/minecraft/server/WorldServer.java
+++ b/src/main/java/net/minecraft/server/WorldServer.java
@@ -1198,6 +1198,7 @@ public class WorldServer extends World implements GeneratorAccessSeed {
                 entity.origin = entity.getBukkitEntity().getLocation();
             }
             // Paper end
+            entity.shouldBeRemoved = false; // Paper - shouldn't be removed after being re-added
             new com.destroystokyo.paper.event.entity.EntityAddToWorldEvent(entity.getBukkitEntity()).callEvent(); // Paper - fire while valid
         }
 
@@ -1210,6 +1211,7 @@ public class WorldServer extends World implements GeneratorAccessSeed {
             this.removeEntityFromChunk(entity);
             this.entitiesById.remove(entity.getId());
             this.unregisterEntity(entity);
+            entity.shouldBeRemoved = true; // Paper
         }
     }
 
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index 6c58b404807c109bacdf6f3d35fbb05329ea8465..47d407af1a770404284c591978978b229cbf7541 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -1032,6 +1032,7 @@ public class CraftWorld implements World {
         for (Object o : world.entitiesById.values()) {
             if (o instanceof net.minecraft.server.Entity) {
                 net.minecraft.server.Entity mcEnt = (net.minecraft.server.Entity) o;
+                if (mcEnt.shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = mcEnt.getBukkitEntity();
 
                 // Assuming that bukkitEntity isn't null
@@ -1051,6 +1052,7 @@ public class CraftWorld implements World {
         for (Object o : world.entitiesById.values()) {
             if (o instanceof net.minecraft.server.Entity) {
                 net.minecraft.server.Entity mcEnt = (net.minecraft.server.Entity) o;
+                if (mcEnt.shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = mcEnt.getBukkitEntity();
 
                 // Assuming that bukkitEntity isn't null
@@ -1077,6 +1079,7 @@ public class CraftWorld implements World {
 
         for (Object entity: world.entitiesById.values()) {
             if (entity instanceof net.minecraft.server.Entity) {
+                if (((net.minecraft.server.Entity) entity).shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = ((net.minecraft.server.Entity) entity).getBukkitEntity();
 
                 if (bukkitEntity == null) {
@@ -1100,6 +1103,7 @@ public class CraftWorld implements World {
 
         for (Object entity: world.entitiesById.values()) {
             if (entity instanceof net.minecraft.server.Entity) {
+                if (((net.minecraft.server.Entity) entity).shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = ((net.minecraft.server.Entity) entity).getBukkitEntity();
 
                 if (bukkitEntity == null) {